Process of forming a charge mixture for producing hydrochloric acid and alkali-silico-aluminate.



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No Drawing.

Specification oi Ilettrs Patent. Application filed October 1l1y1911,Seriallifo. 653,876.

following is a specification. l

The present invention relatesto. a process for manufacturinghydrochloric acid and: alkali-silico-aluminate. i

The object of the inventionis to furnish: aprocess by means of whichwith a furnace? of given capacity, frequent runs may bei I'nade,resulting in uniform products of ai high grade, thereby changing theformeri impracticable and uncommercialexperi- 'ments into a practicableand economical com-Z mercial process.

It has long been known that water vapor will decompose'alkali c'hloridsin the pres-i ence of alumina or silica, or both combined? at elevatedtemperatures. There is 'formcd an alkali oxid which combines with thesilica or alumina, or both, as the case may be, while the freed chlorinunites with the hydrogen from the water vapor, to form hydrochloric'acid gas. Various attempts have been made to use this processcommercially. Among others, -Dr. Adolf Kayser, in British Patent No.11,492 of 1887, proposed decom posin salt with clay and steam in thedownl draft 'form' of furnaces, and there appears; ameth'od' forcarrying this reaction into'effeet U. SL'Patent No. 375,409, of January,1888. All these attempts have been productive of no commercial success(as can be seen from Lungs, Sulphuric Acid and Alkali, Vol. III, 3dedition, 1911, pp. 240; and 250). The cause of non-success in pro-fvious'processes lay in the fact-that there was incomplete conversion ofthe charge mixture, l for the reason that the conversion took place ionly: onthe .surfac e,, and penetrated the block with too great slownessto permit success.

, The result was a'too weak hydrochloric acid,

and an unutilizable aluminate or silicate. Briquets made ofsalt-and-elay alone are not sufiiciently porous to permit the reactionto work commercially and econnmically, asfl" and'others have discovered.

My improred' process relates to theprepfagration of the charge mixture,and to the treatment in the furnace of saidmix-ture.

The essential feature of my mixture is that it shall be thoroughlyporous, and this porosity may be attained in various ways.

In order to get my material into convenient condition for manipulation,I prefer to mix with the charge mass sutfi'cient water to formed intothe'desired'shape; may'ta ke an intimate mixture composed Qf say, -3.0%to. bauxite (preferably the non-ferruginous type) and 30% to 50% alkalichlorid and, make it porous or spongy by one of the methods describedbelow, and use it in the form of bricks, or shavings, or lumps of anydesired shape, the essential feature of my invention being thespong-iness or porosity of the mass, allowing free access of thecombnsparts of the mixture: ,Qr, 15 may form my mixture of clay, aluminaand s1'lica-. ,(or non- ;ferruginous compounds ofalumina and substancewhich shall pass off or evolve a small amount of gas and rendertheabovemixture porous, orspongy, and therefore easily accessible to the furnacegases and to the steam andair in the furnace.

There are various methods bywhich the porosity may beifinpartedtothecharge'mixture. Qne method consists in mixing withthe-silico-alumino-us materials and the alkali chlorid'some substancethat on drying, or on subjection to heatshall be partially driven olf asgas causing expansion, or which shall shrink on heating. Carbon maybemixed in a finely divided state with the other materials and when-theyare subjected to heat in the presence of air,'the carbon will burn andfoim car bonic oX-id and disappear, leaving the charge mixture, spongyor'porousi- Another method consists of combining. with the taric acidand carbonate or bicarbonate of- 'soda. Of course care, mus'the tak n,notf p fuses-any acid or'material which would consilica) together withan alkali'chlorid and ratenmaocafe, 1e12,. A.

render the same 1 plasticg'when -it can be tion gases and'of the steamand -air'to all clay (alumina, silica) and alkali'chlorid taminateeither the hydrochloric acid fumes produced or the material remaining asalkali-silico-aluminate.

To obtain the sponginess when material is mixed in the body of the mass,I find a good composition to be the following: clay (alumina, silica)15% to alkali chlorid 30% to 55%, and a variable amount of volatilematerial, say tartaric acid and carbonate of soda, dependent upon thetemperature, the make-up of the charge, and the degree of porositydesired. Gelatin or glue may be added to the mixture of silicoaluminousmaterial and the salt, which upon addition of water expands and onheating or drying contracts to small volume,'thus leaving: the massporous. Gelatinous alumine and gelatinous silica will act in the samemanner, the mechanically mixed water first passing off and then thechemically combined water, when the bodies will shrink and leave thebodies porous.

The charge is subjected in the furnace to a temperature of l700 to2400-F. The reaction begins at a comparatively low temperature. Itproceeds slowly at first, and it is only when we reach about 1700, witha mixture containing about 32 parts alumina, 46 parts silica and 70parts salt that the reaction is rapid. With this mixture the productformed maintains up to 2000 degrees F. its original shape (brick if thatwas the shape) without melting; The temperature of operation dependsuponthe relative proportion of alumina and silica in the mixture. If aluminapredominates, the temperature is higher, if silica is more abundant, thetemperature at which fusion occurs is lower. Although a new crystallinestructure is given the final product, the process is one that canbec'arr'ied out without fusion. The charge mixture in the shape of aporous mass comprising alkali chlorid mixed with aluminous, orsilico-aluminous material, is now ready to be subjected to the secondstep of the rocess. The charge mixture is fed into a Jrnace where it isexposed to the action of heat, while being acted upon by steam and airor steam alone forced into the furnace and through the mixture. Thefurnace employed may be of any suitable kind,such as a down draft ormuflle, or reverberatory, though I now prefer a furnaceof the tunnel te. The steam actingalone or in conjunction with air and thecombustiongases, .upon the mixture, decomposesthe alkali chlorid, the chlorinthereof uniting with the hydro-- gen and passing ofi to the condensingcham- I here in the form of hydrochloric acid fumes,

the rest of the char remaining behind under the form of alka'-silico-aluminate,

composed of carbon mixed with salt and the' clay materials, as that hasbeen included and claimed in my pending application Ser. No. 637 ,346,filed July 7 1911.

Having thus fully set forth my invention what I claim is 1. The processfor producing a non-combustible charge mixture for making hydrochloricacid and alkali -silicoaluminate, which comprises forming a mixture ofalkali chlorid and silico-aluminous compound andcombining therewith insuch proportions as to produce a non-combustible charge a body adaptedto disappear, treating the mass tocause said body to disappear an leavethe'mass porous. i 2. The process for producing a non-combustiblechargemixture for making hydrochloric acid and alkali silico alummate,which comprises forming a mixture of alkali chlorid and asilico-aluminous material, adding thereto in'such roportions as toproduce a non-combustib e charge a material adapted to pass off andleave the mixture porous, and treating the mass to remove at least apart of said material.

3. The process for producing mixture for making hydrochloric acid andalkali-silico-alumin'ate, which comprises producing shaped bodies bymixing, in such proportions as to produce a non-fuel'charge, clay, salt,and a material adapted to disappear at a temperature of 1700 to 2400degrees Fahrenheit and render the charge mixture porous and preserve itsorlglnal-shape as put intothe furnace.

4. The process of forming a non-combusti ble charge mixture for makinghydrochloric acid and alkali-silico-aluminate, which comprises producingshaped bodies of silicoaluminous materials and an alkali chlorid,

, ALFBED H. oowrnsj Witnesses: 7'

FRANK Nnnn,

ALBERT STETSQN.

a charge

